The Brassica family is a genus of plant that can be found in the mustard and cabbage family. Kohlrabi, kale, broccoli, Brussels sprouts, cabbage and cauliflower all come from the same plant called Brassica Oleracea. There are a few ways to identify Brassicas. One of their characteristic traits is that Brassica flowers always have 4 petals arranged in a cross formation.